Observer Bias

CORE DEFINITION

Observer bias is a type of detection bias, defined as any systematic deviation from accurate information when observing and recording data and information in research. This definition can be further extended to include systematic differences between observed results and true values due to differences among observers. Observer bias refers to the tendency of observers to see what they expect to see rather than what actually exists. This is a common phenomenon in many people's daily lives and can sometimes be a significant problem in scientific research. Observation is crucial to scientific research and activities, so observer bias can also have a major impact on research. When such bias exists, data may be higher or lower than actual, and even if research procedures and experimental design are sound, it can still reduce the validity of the study. Observer bias is especially likely to occur when investigators or researchers have a vested interest in the research results or have strong preconceptions. Combined with ambiguous baseline data and subjective scoring methods, these three factors largely contribute to the occurrence of observer bias.